.tab a {
  border: none;
  margin-top: 1px;
  margin-left: 1px;
  margin-right: 1px;
}

.tab_selected {
  position: relative;
  top: 1px;
}

.tab a:hover {
  margin-top: 0px;
  margin-left: 0px;
  margin-right: 0px;
}